Measured-service telephone-exchange system.



PATENTED FEB. 21, 1905.

M. CRANE. MEASURED SERVICE TELEPHONE EXCHANGE SYSTEM.

APPLIOATION FILED AUG. 31, 1903.

[nae/757" flrzzy 773. Cruz/we UNITED STATES Patented February 21, 1905.

PATENT OFFICE.

HENRY M. CRANE, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

MEASURED-SERVICE TELEPHONE-EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 782,828, dated February 21, 1905.

Application filed August 31,1903. Serial No. 171,346.

To all whom it may concern:

Be it known that I, HENRY M. CRANE, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Measured-ServiceTelephone- Exehange Systems, of which the following is a full, clear, concise, and exact description.

My invention relates to the measurement of IO telephone-service, and has for its object to provide an improved organization of apparatus and circuits for the operation of a servicemeter in association with each line at a telephone-exchange switchboard of the central- 5 battery two-wire type-that is, where only two terminals and their connected conductors are provided for each multiple spring-jack instead of three, as has been common heretofore. The organization of a system of this type so as to retain the standard line-signals and supervisory signals of three-wire systems is a matter of considerable difliculty, and it has been impracticable in such systems heretofore devised to provide also in addition to 5 such signals a service-meter associated with each line at the central switchboard to register each call for which acharge is to be made.

I have devised a two-wire system in which a service-meter is associated with each line.

3 to be actuated in response to a switch associated with the operators cord-circuit. This system is illustrated in the accompanying drawing, which is adiagram indicating asubscrihers line extending from a substation to a central ofiice, with an operators plug-circuit and a portion of the accessory apparatus, the system being organized and equipped in accordance with my invention.

The usual subscribers apparatus is shown 4 at the substation A, including a gravity telephone-switch s, controlling the circuit. At the central oiifice the two line conductors 1 2 are connected to the armatures c 0 respectively, of a cut-off relay 0. The back contacts of said armatures are connected to normal extensions 1 2 of the line conductors leading to the poles of a central battery 6. The pole of the battery which is so connected to conductor 1 is grounded, and a line-signal magnet (Z, which may be a relay controlling a sub- 5 sidiary lamp-signal cl, is included in the normal extension 2 of the other line conductor, 2. The armatures c c of the cut-off relay 0 are provided with front contacts connected with alternate extensions 1 2 of the line leading to the contacts a a respectively, of the several multiple spring-jacks a. The magnet of the cut-off relay is connected in a branch to ground from the conductor 2 to be excited when any jack is plugged into.

The operator is provided with a number of pairs of plugs e e, such as the pair shown, for connecting lines together. Each plug has the usual tip and sleeve contacts e 0 adapted to register with the contacts a a, respectively, 5 of any spring-jack a into which such plug may be inserted. The tip and sleeve contacts of each plug are united with the corresponding contacts of its mate by link conductors 3 at, respectively, ofthe cord-circuit, each of said con- 7 ductors incl uding two windings of the usual repeating-coil. The central battery 7) is connected in a bridge of the cord-circuit between the windings of the repeating-coil, the grounded pole of said battery being on the side which is-connected to conductor 3, leading to the tip-contacts of the plugs. Relays f g are ineluded in the circuit of conductor 4 between the free pole of the battery and the answering and calling plugs, respectively, in the path of 30 current through the cut-ofl relays of the respective lines to which said plugs may be connected. Said relays are adapted when excited to close local circuits through supervisory signal-lamps)" g respectively. Supervisory 5 relaysf g, included in the cord-strand 3 between the battery and the answering and calling plugs, respectively, control short circuits 8 9 about the relay-magnets fg, respectively, so that when relays f g are excited relays 9 fg are short-circuited and inert. Said relays f g are in the path of current controlled at the substation telephone-switches of the lines with which the corresponding plugs may be connected. The result is that when the plugs are in use the lamps f g indicate to the operator the condition of the connected lines, said lamps being lighted when the telephoneswitch is opened at the corresponding sub- 5 scribers station, as when the telephone is replaced on its hook for use.

In accordance with the present invention I provide in association with each line of a system such as illustrated a connection-register or service-meter 7a of the well-known type adapted to count or register each time current of the required strength is passed through its magnet. This service-meter is connected in the system illustrated in a branch 5 from the conductor 1 to contacts a of the multiple spring-jacks a and is shortcircuited by extension 1 of the line when cutoff relay 0 is actuated. The service-meter is also connected in a local circuit extending from the plug-circuit by way of conductor 5 to armature c of the cut-off relay and thence to the grounded pole of battery Z) by way of the back contact of said armature and extensionconductor 1". To operate the service-meter, a switch is provided in association with the operators cord -circuit, said switch being adapted when actuated to connect a suitable source of current in circuit with the servicemeter. 1n the system illustrated the said switch for operating the service-meter is a key is adapted for manual actuation by the operator, said key being adapted when operated to break the normal circuit of link conductors 3 L and connect the free pole of battery Z1 with the tip-contact 0' of the plug instead of with the sleeve-contact, as before, and also to connect the sleeve-contact through the relay f to earth. The relay f is cut out. If desired, an operators position-meter Zmay be included in the conductor 6, which leads from the free pole of battery 5 through the alternate contacts of key 7i: to the tip of the plug, so that this meter will be caused to count or register each time the key is depressed to register a call on a subscribers meter and will serve both as a check upon the indications of the several subscribers meters and also to indicate the amount of work performed by the operator.

The subscribers service-meter may be arranged to act also as a relay in a well-known manner to close a contact when the servicemeter is actuated. I have illustrated such a contact 72/ in association with the service-meter IL, controlling a conductor 7, which leads from the free pole of battery 6 through a resistance m to the conductor 2, and so to the thimbles a of the several multiple jacks, with which thimbles the sleeve-contact of the operators plug is adapted to register.

In the operation of the system illustrated the subscribers service-meter is intended to be actuated after the subscriber has hung up his telephone at the end of a conversation. During connection with the line it is shortcircuited as to currents from the bridged battery of the plug-circuit by the armature c and its front contact of the cut-off relay 0, which constitute a preventive device for rendering the meter unresponsive to the normal operating-currents of the line; but when the key A: is depressed the connection of battery 7) with the plug-contacts is reversed, and the cut-off relay being in a ground branch from conductor 2 no longer receives current, so that it allows its armatures to fall back. The service-meter it is then left in a ground branch 5 1 from the conductor 1. Current. is applied from the free pole of battery 7) by way of conductor 6, leading through the operators meter Z and contacts of key l; to the tip of the inserted plug and thence through the meter 7i and conductor 1 to earth. Both meters it and Z are thus caused to register, and at the same time the closure of contact it by the subscribers meter it applies battery in the circuit 7 2 to the sleeve of the plug and to earth through the relay f, whereby said relay is excited and causes signal-lampf to be lighted. The flashing of this lamp when the key l; is depressed serves as an indication to the operator that the subscribers meter has been properly actuated.

The resistance 011, cu t-olf relay 0, and supervisory relayf are so proportioned to one another that the supervisory relay will be excited and the cut-off relay will remain inert when current is applied through said resistance m.

It will be noted that the subscribers service-meter is well protected against accidental operation, since it is short-circuited when the line is in use, except at the instant of counting, and when the line is not in use the meter is protected by a dead-ground on the line side. 7

It is evident that any suitable return-conductor may take the place of the ground connections, and the claims should be read and understood accordingly.

I claim- 1. The combination with a telephone-line in a two-wire exchange switchboard-circuit, of a spring-jack for the line, a plug and plug-circuit, a service-meter connected with a contact of the spring-jack, a cut-off relay in a local branch circuit closed in making connection with the line, a shunt of the service-meter closed by said relay when excited, a source of current, and a switch 7; associated with the plug-circuit, and connections for said switch adapted to render the cut-off relay inert and apply current to the service-meter when said switch is actuated, substantially as set forth.

2. The combination with a telephone-line extending from asubstation to a central office, of a spring-jack for the line, a plug and plugcircuit for making connection therewith, a source of current in the plug-circuit, a cut-elf relay in abranch circuit closed in making connection with the line, a service-meter in series in one of the line conductors leading from the spring-jack, a shunt of the service-meter closed by a contact of the cut-oif relay when excited, a return-circuit for the service-meter established at a back contact of said cut-off relay, and a switch associated with the plug-circuit, adapted to divert current from the cut-off relay and apply current in the service-meter circuit.

3. The combination with a metallic-circuit telephone-line extending from a substation to a central office, of a spring-jack for the line having two contact-terminals, a grounded central battery and a line-signal magnet, 21 cutoff relay having contacts normally connecting said battery and line-signal magnet with the line, alternative connections of the line conductors to the respective spring-jack terminals, established by said cut-oif relay when excited, a plug and plug circuit having said central battery connected in a bridge thereof, a branch circuit including said cnt-ofl relay connected between one of the spring-jack contacts and the grounded pole of the battery, a service-meter in a ground branch from the other contact of the spring-jack, said branch being controlled at a back contact of said cutoff relay, aswitch associated with the plug-circuit adapted to reverse the connections of the battery with the plug, whereby the cut-off relay is rendered inert and the service-meter actuated, and a supervisory signal device in the plug-circuit, controlled in the operation of said service-meter.

4:. The combination with a telephone-line extending from a substation to a central oflice, of a service-meter connected with the line, a preventive device for rendering the servicemeter normally unresponsive to current in the line, means at the central office under the control of the operator for counteracting said preventive device to render the service-meter responsive, a source of current, and a switch for directing current from said source over the line to operate the meter.

5. The combination with a telephone-line, of a service-meter connected in the circuit of the line, an electromagnetic switch, a circuit controlled thereby adapted to render said service-meter unresponsive to the normal operating-currents of the line, means for operating said switch to render said meter responsive, a source of current, and a switch adapted to apply current to the line to actuate said meter.

6. The combination with a telephone-line, of a service-meter having a winding included in the circuit of the line, a shunt-circuit of the service-meter adapted when closed to render the meter unresponsive to the normal operating-currents of the line, a relay adapted when operated to close said shunt-circuit, a winding for the relay connected with the telephoneline, a connection-switch for making connection with the line, an actuating-circuit for said relay completed in contacts of the connectionswitch, switch-contacts controlling said actuating-circuit to render the relay inert, and other switch-contacts adapted to apply current to the line to operate the meter.

7. The combination with a telephone-line extending to a connection-terminal at a central oflice, of a plug and plug-circuit for making connection with the line at the terminal thereof, a service-meter connected with the line at the central ofiice, switch-contacts actuated in making connection with the line controlling a circuit of the service-meter and adapted to render the same inoperative,switchcontacts associated with the plug-circuit and means controlled thereby adapted to bring the service-meter into operative relation with the telephone-line, a source of current, and other switch-contacts of the plug-circuit for applying current to the line to actuate the servicemeter.

8. The combination with a telephone-line extending in two limbs from a substation toa connection-terminal at a central office, of a plug and plug-circuit for making connection with the line at-the connection-terminalthereof, a battery in the plug-circuit, a relay having a winding in a branch circuit from one limb of the line closed to actuate the relay in making connection with the line, a servicemeter having a winding connected with the .other limb of the line, switch-contacts of the relay controlling the circuit of the service-meter to render said meter inoperative during connection with the line, and a switch in the plug-circuit adapted to control the application of current to the line, whereby the relay may be rendered inert to bring the service-meter into operative relation with the line, while current is applied to the service-meter to operate In witness whereof I hereunto subscribe my name this 29th day of June, A. D. 1903.

HENRY M. CRANE. Witnesses:

(J, CAMPBELL, H. F. WHITE. 

